This invention relates to fluid displacement apparatus, and in particular, to fluid compressor units of the scroll type.
Scroll type apparatus has been well known in the prior art as disclosed in, for example, U.S. Pat. No. 801,182, and others, which discloses a device including scroll members each having an end plate and a spiroidal or involute spiral element. Scroll members are maintained angularly and radially offset so that both spiral elements interfit at a plurality of line contacts between the spiral curved surfaces to thereby seal off and define at least one fluid pocket. The relative orbital motion of these scroll members shifts the contact line along the spiral curved surfaces and, therefore, the fluid pocket changes in volume. The volume of the fluid pocket increases or decreases dependent on the direction of the orbital motion. Therefore, scroll type apparatus is applicable to compress, expand or pump fluids.
In comparison with conventional compressors of the piston type, a scroll type compressor has certain advantages such as fewer number of parts, continuous compression of fluid and others. However, there have been several problems; primarily sealing of the fluid pocket, wearing of the spiral elements, and inlet and outlet porting.
Although there have been many patents, for example, U.S. Pat. Nos. 3,884,599, 3,924,977, 3,994,633, 3,994,635, and 3,994,636 directed to resolving these and other problems, the resultant compressor is complicated in construction and in production.
It is desired that the fluid introduced into the compressor housing be reliably taken into all the fluid pockets between both scroll members, in order to effectively compress the fluid.
Furthermore, in order to increase compressive capacity and compression ratio, it is required that the number of turns of each spiral element be increased. This means that the radius of the compressor housing is also increased.
Additionally, a compressor unit of the scroll type should be provided with a lubricating system for lubricating its moving parts.